2019 Impact factor 2.176
Hadrons and Nuclei


Eur. Phys. J. A 14, 169-178 (2002)
DOI: 10.1140/epja/i2002-10004-2

Langevin description of charge fluctuations in fission of highly excited nuclei

A.V. Karpov and G.D. Adeev

Department of Theoretical Physics, Omsk State University, Mira prospect 55-A, Omsk, 644077 Russia

karpov@phys.omsu.omskreg.ru
adeev@univer.omsk.su

(Received: 22 October 2001 / Revised version: 25 March 2002 Communicated by J. Äystö)

Abstract
A stochastic approach to fission dynamics based on three-dimensional Langevin equations is used to study charge fluctuations in fission of highly excited nuclei. Elongation, neck and charge asymmetry parameters are chosen as relevant collective coordinates. Using as an example $\rm ^{4}He+^{232}Th$ induced fission of $\rm ^{236}U$ in a broad range of excitation energies (from 60 to $160 \mbox{ MeV}$), the isobaric charge variance is investigated to obtain information on nuclear dissipation. The friction parameter of the charge mode is calculated under the assumption of both the one-body and two-body mechanisms of nuclear viscosity. The results obtained for the variances of the charge distribution within the applied approach reveal that the optimal reproduction of the available data is achieved with the value of the two-body viscosity coefficient $(0.6\le\nu_0\le 1.8)\times 10^{-23}\mbox{MeV s fm}^{-3}$ that is close to those deduced earlier from the description of the fission fragment mass-energy distribution. The expression for the friction parameter of the charge mode is derived within the one-body mechanism of nuclear dissipation. The one-body mechanism of nuclear dissipation also provides a good reproduction of data on the isobaric charge variance without any adjustable strength parameter.

PACS
25.85.-w - Fission reactions.
05.10.Gg - Stochastic analysis methods (Fokker-Planck, Langevin, etc.).
02.50.Ey - Stochastic processes.

© Società Italiana di Fisica, Springer-Verlag 2002